So it basically cleaned up the working directory.
This comes very handy when you have to fix something on your last commit, but you already made some progress on the other part of your application.
With this command you basically put your changes elsewhere and you're able to commit that fix.

If you execute git stash apply now, the last added item will be pulled out of the stash and merged with master (stashes really follow LIFO principle).
We can still merge an item named “fixing humanized attributes” like this:

This is not the only scenario where stash comes handy. It also does when you wish to switch branches, rollback states, but would like to keep your current changes.

It's also nice to clean up your stash regularly so you don't get lost in too many items. You can do that with git stash clear, but be careful with it since it doesn't ask you to confirm your little stashocide.